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Biomedical subjects

M C Adams

Publications and source records attributed to M C Adams.

At least 37 records · Page 2Linked to original sources
PubMed1999

Repair of hypospadias complications using the previously utilized urethral plate.

OBJECTIVES: To review our results of patients who underwent repeat hypospadias surgery using local skin flaps with preservation of the urethral plate. METHODS: We retrospectively reviewed the medical records of all patients who underwent a reoperative hypospadias repair using the urethral plate between 1988 and 1996. A total of 53 patients were identified who developed either a large fistula (47 patients) or severe stricture (6 patients) after the initial repair. Seventeen patients underwent a repeat Mathieu flip-flap and 36 an onlay flap. The mean age at the time of surgery was 5.2 years (range 1 to 27). The mean duration of follow-up was 17 months (range 6 to 108). RESULTS: The initial failed hypospadias repair was corrected with a single procedure in 44 (83%) of the 53 patients. The 9 patients who had further complications required 17 additional procedures. A meatal-based flap had been used in 4 of these patients and an onlay flap in 5. Three of the 9 patients who had further complications presented with urethral strictures after the previous repair. CONCLUSIONS: Fistula and stricture are common complications of hypospadias surgery. The use of the urethral plate in primary repairs has helped decrease the complication rate. We report the effectiveness of using local skin flaps and preserving the urethral plate in complex reoperative hypospadias surgery. These techniques were successful in 83% of these challenging patients. Patients with stricture after hypospadias surgery are at increased risk of further complications.

Adolescent↗
PubMed1999

How they begin and how they end: classic and new theories for the development and deterioration of congenital anomalies of the kidney and urinary tract, CAKUT.

CAKUT are problems that often require surgical intervention or, in the worst case, lead to renal failure and the need for dialysis and/or renal transplantation. It is believed that these anomalies share a common genetic cause and to date there has been no good animal model with which to study these abnormalities. Although the abnormal interaction between the ureteral bud and metanephric blastema leads to renal hypodysplasia, vesicoureteral reflux, and ectopic ureters to name a few, the genetic and biochemical modulation of urinary tract development is not understood. Studies using the mouse strain mutant for angiotensin type 2 (AT2) receptors have given new insight into this mystery. The animals show defective apoptosis of undifferentiated mesenchymal cells in the area surrounding the developing kidney and urinary tract. This abnormal apoptosis may well interfere with the normal interaction between the ureteral bud and metanephric blastema resulting in CAKUT. This abnormal interaction would theoretically lead to preexisting intrinsic abnormalities of the kidney, which are programmed and take effect early in embryonic development. In the worst cases, the renal abnormalities would lead to progressive deterioration of renal function. Undoubtedly, there are more genes and biochemical modulators involved in this process other than the RAS and AT2 receptors. Our current animal model gives new and unique possibilities with which to study development of the kidney and urinary tract and ultimately seek ways of preventing an often debilitating disease process.

Animals↗
PubMed1999

Coronal cuff: a problem site for buccal mucosal grafts.

PURPOSE: Urethral reconstruction of complex hypospadias or epispadias continues to present a significant challenge. Buccal mucosa as an onlay or tube graft is an excellent option when faced with paucity of penile skin. We identified the factors that lead to success or failure in these repairs. MATERIALS AND METHODS: During 6 years we placed 34 buccal mucosal grafts in 31 patients to repair complex hypospadias and epispadias. Penile skin was preferentially used for urethroplasty but a free buccal mucosal graft was used for reconstruction due to lack of adequate penile skin. The cases were complicated with an average of 5 previous unsuccessful repairs each in 16. Grafts ranged from 1.5 to 10 cm. and 10 patients required pieced grafts. We created 1 combination, 16 onlay and 17 full tube grafts. Buccal mucosa was used with a Thiersch-Duplay urethroplasty in 8 patients. RESULTS: Anastomotic stricture in 5 patients was proximal in 4. Fistula was a complication in 13 grafts that generally developed on the distal shaft, particularly at the coronal cuff. Of the 7 patients who underwent proximal Thiersch-Duplay urethroplasty with a distal buccal graft 6 had a coronal fistula. Fistula was more common with tube and pieced than with onlay grafts. CONCLUSIONS: Fistula is overwhelmingly the most common complication after buccal mucosal graft urethroplasty. Most fistulas develop at the coronal cuff, and we suspect that skin coverage and potential blood supply have not been good in that region. Anticipation of this problem during stage 1 of hypospadias repair would allow more advantageous distribution of the existing penile skin. Good distal skin coverage cannot be compromised in these complex cases.

Adult↗
PubMed1998

Feminizing genitoplasty: state of the art.

Surgical management of intersex states continues to evolve such that today's efforts achieve near normal cosmetic and functional results. In this article we discuss the reconstruction of the female genitalia in those that have had significant androgen stimulation as well as those with near normal external genitalia but significant urogenital sinus anomalies. The initial evaluation as well as postoperative follow-up management is addressed.

Clitoris↗
PubMed1998

Ureterocystoplasty: is it necessary to detubularize the distal ureter?

PURPOSE: The conventional technique for ureterocystoplasty includes complete mobilization and incision of the ureter. We describe a modified procedure in which the distal 3 cm. of ureter are left in place and intact. MATERIALS AND METHODS: This modification has been used in our last 13 cases of ureterocystoplasty. The first 7 patients with followup of more than a year (mean 28 months) are included in this series, and 6 have undergone video urodynamic evaluation before and after reconstruction. RESULTS: Clinical results have been good. Four patients who have been toilet trained are continent. There have been no problems from stagnant urine in the intact ureter with only 1 case of pyelonephritis and no bladder calculi. Mean bladder capacity on cystometrogram has increased from 103 to 236 ml. after reconstruction and reached 137% of expected capacity for age and size (range 110 to 155%). No uninhibited contractions or problems with compliance have been noted. CONCLUSIONS: The distal ureter may be left intact for ureterocystoplasty to protect ureteral blood supply. This modified technique is sound from a physiological standpoint, technically easier and associated with good results.

Adolescent↗
PubMed1998

Rabbit urethral regeneration using small intestinal submucosa onlay grafts.

OBJECTIVES: To determine if small intestinal submucosa (SIS) can evoke urethral regeneration. METHODS: Twenty male white New Zealand rabbits were assigned to one of three experimental groups. Group 1 (n = 4) underwent simple urethrotomy and closure. Group 2 (n = 8), a second control group, underwent an onlay urethroplasty with a graft of full-thickness preputial skin from the host rabbit. Group 3 (n = 8) underwent an onlay urethroplasty with an SIS graft. RESULTS: All eight SIS onlay grafts promoted regeneration of the normal rabbit epithelium supported by a well-vascularized collagen and smooth muscle backing. Preputial free onlay grafts maintained a keratinizing squamous cell epithelium with a poor supportive backing, which resulted in the formation of urethral diverticulum. CONCLUSIONS: SIS onlay patch grafts for urethroplasty promote rabbit urethral regeneration.

Animals↗
PubMed1998

Natural history of refluxing distal ureteral stumps after nephrectomy and partial ureterectomy for vesicoureteral reflux.

PURPOSE: We evaluated the natural history of refluxing distal ureteral stumps after nephrectomy and partial ureterectomy. MATERIALS AND METHODS: Between 1985 to 1996, 38 patients a mean age of 37 months underwent nephrectomy and partial ureterectomy for reflux into a nonfunctioning kidney. The diagnosis included primary reflux in 23 patients, reflux associated with posterior urethral valves in 10 and ipsilateral ureterocele in 5. Mean followup was 45 months. RESULTS: Only 1 patient with an ipsilateral ureterocele and 1 with contralateral reflux (5%) had symptomatic infections during postoperative followup, and each underwent a secondary procedure to remove the ureteral stump. No patient with only primary unilateral reflux required surgery for the refluxing stump. CONCLUSIONS: Because of the low risk of morbidity associated with a refluxing ureteral stump, we recommend nephrectomy and proximal ureterectomy in patients with reflux into a nonfunctioning kidney.

Adolescent↗
PubMed1998

Renal angiotensin converting enzyme promotes renal damage during ureteral obstruction.

PURPOSE: We and others have shown that angiotensin II has a pivotal role in renal damage in various renal injuries. Although most angiotensin II actions are associated with the angiotensin type 1 receptor, there is increasing evidence that the angiotensin type 2 receptor also transduces some important effects of angiotensin II. In this regard we recently observed that mice with genetically engineered disruption of the angiotensin type 2 receptor, termed Agtr2 mutants, are more susceptible to structural renal damage after ureteral obstruction. Recent evidence suggests that a genetically determined increase in angiotensin converting enzyme activity in humans promotes end organ damage. Therefore, we determined whether renal damage in Agtr2 mutants is associated with heightened angiotensin converting enzyme activity. MATERIALS AND METHODS: We studied 28 wild type and 19 Agtr2 mutant mice with unilateral ureteral obstruction. Seven days after obstruction was created serum samples were obtained to evaluate angiotensin converting enzyme activity. The obstructed and contralateral kidneys were harvested for histological analysis and determination of renal angiotensin converting enzyme activity by high pressure liquid chromatography. RESULTS: Renal angiotensin converting enzyme was uniformly higher than serum angiotensin converting enzyme in normal wild type and Agtr2 mutant mice. However, even at baseline Agtr2 mutant mice had strikingly higher renal angiotensin converting enzyme activity than normal wild type mice (mean plus or minus standard error 1,492+/-83 versus 450+/-60 milliunits per gm. tissue weight, p <0.0005). Histological analysis revealed more extensive parenchymal damage in the obstructed kidneys of mutant mice than in identically treated controls. Notably while unilateral ureteral obstruction decreased renal angiotensin converting enzyme activity in each group, activity remained persistently higher in the Agtr2 mutants than in normal mice (mean 742+/-146 versus 310+/-43 milliunits per gm. tissue weight, p <0.005). CONCLUSIONS: We propose that elevated renal angiotensin converting enzyme activity contributes to more severe renal parenchymal damage in ureteral obstruction by promoting the availability of growth factors, such as angiotensin II, or depleting antiproliferation factors, such as bradykinin or nitric oxide. These findings complement previous observations that angiotensin converting enzyme inhibition preserves the renal parenchyma after injury, including obstruction.

Animals↗
PubMed1998

Etiology, management and surgical complications of congenital chordee without hypospadias.

PURPOSE: We comprehensively evaluated the etiology, management and surgical complications of chordee without hypospadias. MATERIALS AND METHODS: We reviewed the records of patients who underwent chordee correction between January 1985 and December 1996. A total of 87 patients with a median age of 14 months were treated for chordee without hypospadias. Mean followup was 10 months. Patients were treated in the standard fashion and a straight phallus was confirmed in all postoperatively. We grouped cases according to the etiology of chordee, including skin tethering, fibrotic dartos and Buck's fasciae, corporeal disproportion and urethral tethering. RESULTS: Of the 87 patients 28 (32%) were successfully treated with release of the skin and superficial fascia. In 29 cases (33%) extensive resection of the fibrotic dartos and Buck's fasciae was necessary to straighten the phallus, including 2 (7%) in which chordee recurred. Corporeal disproportion was identified in 24 patients (28%), of whom 2 (8%) also had complications (urethrocutaneous fistula and recurrent chordee in 1 each). In 6 cases (7%) urethral tethering was the etiology of chordee, of which 3 (50%) had complications (urethrocutaneous fistula and recurrent chordee in 2 and 1, respectively). Overall 80 of the 87 patients (92%) were successfully treated with 1 operation. CONCLUSIONS: In our series the etiology of chordee without hypospadias was evenly divided among skin tethering, fibrotic dartos and Buck's fasciae, and corporeal disproportion. A congenitally short urethra was a rare cause of isolated chordee. Surgical correction is highly successful with a low 8% complication rate.

Adolescent↗
PubMed1998

Role of the renin-angiotensin system in disorders of the urinary tract.

PURPOSE: The role of the renin-angiotensin system in the homeostasis of fluid, electrolyte and blood pressure has been known for quite some time. Recent developments indicate that angiotensin has a profound role, not only in the developing urinary tract but also in the response of the urinary tract to injury. In this review we outline these characteristics. MATERIALS AND METHODS: We summarize the clinical approach to congenital abnormalities of the kidney and urinary tract, and report new data obtained in genetically engineered mice. Furthermore, we present the connection between the mutant mice observations and human congenital abnormalities. RESULTS: Genetically engineered mutants clearly indicate that the renin-angiotensin system is important for normal renal and urological development. As in glomerular disease, the renin-angiotensin system is involved in progressive damage due to urological disease. CONCLUSIONS: While the renin-angiotensin system is important for blood pressure regulation, it also affects the embryogenesis of the urinary tract and modulates renal injury due to specific disease processes. The importance of angiotensin and its blockade provides an exciting avenue for possible early treatment in children with congenital anomalies of the kidney and urinary tract.

Animals↗
PubMed1998

Prenatal urinary ascites and persistent cloaca: risk factors for poor drainage of urine or meconium.

PURPOSE: The unique confluence of the urinary, genital and gastrointestinal tracts in girls with persistent cloaca potentially results in aberrant drainage of urine and meconium that may be characteristic, allowing a prenatal diagnosis to be made. MATERIALS AND METHODS: Three of our last 15 patients with cloacal anomalies presented with urinary ascites due to intraperitoneal reflux through the genital system. In 3 female patients a long, narrow cloaca was associated with a high confluence of the urethra, vagina and rectum. All 3 patients ultimately underwent creation of a cutaneous vesicostomy. RESULTS: In all 3 cases cutaneous vesicostomy effectively diverted urine away from the cloaca before definitive repair. CONCLUSIONS: The urethra-like persistent cloaca may result in significant outflow resistance. When combined with high confluence, it may cause aberrant drainage of urine and/or meconium. When such problems are noted prenatally, they are likely to persist postnatally and require intervention.

Ascites↗
PubMed1997

Principles in management of complex pediatric genitourinary plexiform neurofibroma.

Neurofibromatosis is a hamartomatous disorder of neural crest derivation characterized by cutaneous pigmentation and tumor formation in various tissues. Visceral involvement is typically insidious, progressive, and difficult to treat. Plexiform neurofibroma of the urinary tract is rare. Involvement of nearly every genitourinary structure by these lesions has been reported, with the bladder being most commonly involved. In part due to the small number of patients seen at any one institution and the highly variable location and extent of this disease process, a plan for management of individuals with genitourinary neurofibromatosis has not been proposed. In an attempt to define specific goals in treatment of such patients, we reviewed our population of 260 pediatric patients with type 1 neurofibromatosis. We present our series of 5 patients with complex genitourinary lesions and describe specific management principles.

Adolescent↗
PubMed1997

Upsizing of the artificial urinary sphincter cuff to facilitate spontaneous voiding.

OBJECTIVES: Following placement of an artificial urinary sphincter (AUS) in the male child, functional and mechanical alterations can ensue, resulting in an inability to void spontaneously. One possible mechanical etiology in the patient entering puberty is prostatic growth within the fixed mechanical confines of the AUS cuff, resulting in progressive bladder outlet obstruction. Unrecognized infravesical obstruction can, in turn, lead to upper urinary tract deterioration, sepsis, or renal failure. We evaluated the effect of somatic growth and maturation of the male urethra on voiding dynamics in boys with an AUS to specifically determine whether revision of the sphincter cuff (ie, upsizing) is beneficial in restoring the ability to void spontaneously. METHODS: A retrospective review of 124 children with an AUS was performed. Eleven boys were identified whose bladder neck cuffs were later upsized in an attempt to improve bladder emptying. All boys were prepubertal at the time of original cuff placement. The average interval between the initial operation and cuff upsizing was 5 years. RESULTS: Following original sphincter placement, 8 patients emptied to completion spontaneously and 3 patients emptied by intermittent catheterization. All eight of the spontaneous voiders experienced progressive difficulty emptying after they entered puberty and ultimately had to rely on clean intermittent catheterization to empty completely. Follow-up subsequent to cuff exchange averaged more than 5 years (range 1 to 10 years). Despite an average increase of 10 mm in cuff size, all patients continued to depend on intermittent catheterization to empty completely. CONCLUSIONS: Upsizing the bladder cuff in the maturing male who experiences difficulty with bladder emptying does not restore the ability to void spontaneously.

Child↗
PubMed1997

Genital malformations and coexistent urinary tract or spinal anomalies in patients with imperforate anus.

PURPOSE: Urinary tract malformations have been described in up to 50% of patients with imperforate anus but genital anomalies have been less well analyzed in the same patient population. We sought to evaluate the frequency of coexisting genital, urinary and spinal malformations in a population with imperforate anus. MATERIALS AND METHODS: We reviewed 128 cases of imperforate anus, focusing on genital malformations and their relationship to anomalies of the urinary tract and spine. The series included 69 boys and 59 girls with low (59), intermediate (22) and high (47) imperforate anus. RESULTS: Boys were much more likely to have a genital or upper urinary tract problem than girls (26 or 50 versus 5 or 30%, respectively). The risk for both sets of problems increased with the level of the anorectal lesion. The incidence of genital malformations increased from 14 to 26% in the presence of a renal lesion and from 10 to 23% with an associated spinal problem. Conversely, the incidence of urinary and spinal anomalies increased in patients with genital malformations. CONCLUSIONS: The genitalia of children with imperforate anus should be carefully examined. Patients with anorectal malformations should also be evaluated for urinary tract and spinal problems. The yield of such studies increases in patients with recognized genital malformations.

Abnormalities, Multiple↗
PubMed1997

Management of ectopic ureters: experience with the upper tract approach.

PURPOSE: The necessity of removing the ureteral stump after upper tract surgery for an ectopic ureter has been debated. We reviewed the records of patients initially treated at the kidney level to evaluate indications for later stump removal. MATERIALS AND METHODS: We reviewed the medical records of 32 patients with 33 ectopic ureters treated at the kidney level during the last 10 years. RESULTS: Ectopic ureters were associated with duplicated collecting systems in 31 cases and with single systems in 2. Upper pole heminephrectomy and partial ureterectomy were performed in 23 units and upper tract reconstruction was done in 8. Both patients with single systems underwent nephrectomy. Four patients (12%) required repeat surgery at the bladder level, including 1 who underwent ureteral reimplantation for persistent ipsilateral lower pole reflux and simultaneous upper pole stump removal. Preoperative voiding cystourethrography revealed reflux into the ectopic ureter in 1 patient with postoperative reflux and infections. The remaining 2 patients required a repeat operation to remove the stump due to recurrent urinary tract infections and newly detected reflux into the stump, respectively. CONCLUSIONS: The majority of patients with ectopic ureters can be treated by addressing only the upper urinary tract. No patient who presented with incontinence required ureteral stump removal. Whether noted preoperatively or postoperatively, reflux into the ectopic ureter necessitated ureteral stump removal. Three of the 6 patients (50%) who had reflux to the ipsilateral kidney required lower tract surgery.

Abnormalities, Multiple↗
PubMed1997

Reconstruction of the high urogenital sinus: early perineal prone approach without division of the rectum.

PURPOSE: Reconstruction of the vagina and external genitalia in the infant is quite challenging, particularly when a urogenital sinus is associated with high confluence of the vagina and urethra. Many surgeons believe that children with such a malformation should undergo staged or delayed reconstruction, so that vaginoplasty is done when the child is older and larger. Vaginoplasty early in life is thought to be difficult due to patient size and poor visualization. The posterior sagittal approach has been beneficial for acquiring exposure to high urogenital sinus anomalies but it has been thought to require splitting of the rectum and temporary colostomy. We report a modification of this technique. MATERIALS AND METHODS: In the last 5 years all patients with urogenital sinus anomalies underwent reconstruction using a single stage approach regardless of the level of confluence. In 8 patients with a high level of confluence reconstruction was performed using a perineal prone approach. Exposure was achieved without division of the rectum. The operative technique is presented in detail. RESULTS: This midline perineal prone approach has allowed excellent exposure of the high vagina even in infants. In all 8 patients reconstruction was done without difficulty and no patient required incision of the rectum or colostomy. This procedure did not preclude the use of a posteriorly based flap for vaginal reconstruction. CONCLUSIONS: While patients with low confluence can be treated with single posteriorly based flap vaginoplasty, those with higher confluence may benefit from a perineal prone approach to achieve adequate exposure for pull-through vaginoplasty. This prone approach to the high urogenital sinus anomaly can be performed without division of the rectum, provides excellent exposure of the high confluence even in small children and does not preclude the use of posterior flaps for vaginal reconstruction.

Abnormalities, Multiple↗
PubMed1996

Regenerative urinary bladder augmentation using small intestinal submucosa: urodynamic and histopathologic assessment in long-term canine bladder augmentations.

PURPOSE: To evaluate small intestinal submucosa (SIS) as a possible bladder augmentation material. MATERIALS AND METHODS: Nineteen male dogs underwent 35 to 45% partial cystectomy with immediate augmentation with SIS grafts. All dogs were evaluated pre- and postoperatively with blood chemistries, urine cultures, intravenous urograms, cystograms and cystometrograms. Postoperatively (1 to 15 months), bladders were examined with routine histology and image analysis. RESULTS: All dogs survived their intended survival period without morbidity. All results were normal. Histologically, all 3 layers (mucosa, smooth muscle, serosa) of the normal bladder showed evidence of regeneration. CONCLUSIONS: Small intestinal submucosa acts as a scaffold for bladder augmentation through regeneration and could be a potential option for bladder reconstruction.

Animals↗